Preparation of Hemicellulose Nanoparticle-Containing Ionic Hydrogels with High Strength, Self-Healing, and UV Resistance and Their Applications as Strain Sensors and Asymmetric Pressure Sensors

作者：Xiaoqi Gong, Chenglong Fu, Nur Alam, Yonghao Ni, Lihui Chen, Liulian Huang, Hui‐Chao Hu · 发表于：Biomacromolecules · 年份：2022 · DOI：10.1021/acs.biomac.1c01640 · 被引用次数：39 · 研究领域：Advanced Sensor and Energy Harvesting Materials、Hydrogels: synthesis, properties, applications、Electrospun Nanofibers in Biomedical Applications

Smart functional fillers can significantly enhance the comprehensive properties of ionic hydrogels, such as their mechanical properties, which are key features of hydrogels in wearable sensor applications. As a plant-derived natural polymer, hemicellulose can serve as smart functional fillers. In this study, tannic acid-modified hemicellulose nanoparticles (TA@HC) and Fe 3+ were used in the preparation of PAA/TA@HC/Fe 3+ hydrogels. The addition of TA@HC and Fe 3+ in the sodium persulfate (SPS) and acrylic acid (AA) polymerization system resulted in a fast gelation process that was completed within a short time (as short as 30 s) at room temperature. The catechol-rich TA and Fe 3+ system allows for quick activation of SPS to produce free radicals, generating abundant hydroxyl groups in a short period of time, which was responsible for the fast gelation. Furthermore, due to the TA@HC effect and the dynamic catechol (TA)-Fe 3+ redox system, the PAA/TA@HC/Fe 3+ hydrogel exhibited excellent mechanical properties with an exceptionally high strain (as high as 5600%), adhesiveness, rapid and efficient self-healing ability, and reproducible self-adhesion onto various substrates. More importantly, asymmetric adhesive PAA/TA@HC/Fe 3+ hydrogels were prepared by selective Fe 3+ coating of the upper hydrogel surface to render the top surface nonadhesive so that the same hydrogel with different adhesiveness between the upper and bottom surfaces was obtained. The asymmetric adhesive hydrogel...